What are the shortcuts for the pie menus?
Mode

Ctrl+↹ Tab



Proportional Editing Falloff

⇧ Shift+O



Snapping

This one is not a pie menu, but its shortcut seems to be missing from the tooltip as well, so I included it in the list:

Ctrl+⇧ Shift+↹ Tab



Snap

⇧ Shift+S



Pivot Point

.



Transform Orientation

,



Shading

Z